Case Weighing

[Roudy]

I'm working on load development for a new .223 bull barrel.  I've reloaded for many years and usually weigh all my powder charges and cast bullets, but until now I've never weighed my cases....usually just trimmed consistently.

Does anyone weigh their cases? if so:

1.  What kind of tolerance do you use, +/_ .5 gr, +/_ 1.0 gr, ?

2.  If one trims to the same length then weighs the cases is it still important to sort by brand?

Thanks,
Roudy

[Fred M]

Roudy

Weighing cases is a waste of time, it does very little if anything to accuracy in a hunting rifle or for that matter any other rifle.

The specific gravity of brass is 8.6,  say three grains of brass = 1/3gr of water volume or about 0.3gr of powder. Most powder measures don't throw charges that good.

Even with BR 6ppc cases I never weigh cases. You do more good with your time uniforming primer pockets and flash holes and partial neck turning.

[Ditchdigger]

I had never weighed my case's before,but I do on my latest rifle in 243. Just for the heck of it I put aside the case's that threw flyers that opened the groups up to 1". And just before I loaded the case's that made 1 hole again I weighed them. They were all within 1tenth of a grain. So I trimmed every case that I had,and weighed them and sorted them to within 1 tenth of a grain. The rifle startd shooting 5 shot groups of .380" consistantly after that. Now I can work on different loads an overall lenghts to get it down even more I hope. It's getting close to my bolt gun's now.    Digger

[Roudy]

Fred,

I agree that weighing each case is probably useless for hunting applications.  My objective in this load development is to find the powder and bullet combination that provides the best accuracy, from that point on I'll just trim consistently and keep cases sorted by headstamp. 

I've never turned my case necks before and have only cleaned the primer pockets.  When you mention uniforming the flash holes....do you just use a drill, or do you use a special reamer?

Ditchdigger...3/8 of an inch is a mighty small group.  Don't thimk I'm going to sort to .1 grain, probably +/- .5 grain, at least to start.  Want to get my groups down to minute of groundhog at 300 yards.

Roudy

[Fred M]

Roudy.

Quote.
I've never turned my case necks before and have only cleaned the primer
 pockets.  When you mention uniforming the flash holes...
.do you just use a drill, or do you use a special reamer

There is a tool that does remove the burrs on the inside and at the same time reams the flash holes to an even size. After removing the burrs it puts a small bevel on the inside flash hole giving the primer flash circular even spread.

You can drill the flash holes to the same size.

The primer pocket uniforming tool is a reamer that makes the pockets all the
same depth.

These three items contribute more to accuracy than any amount of case weighing.
That is neck concentricity and shot to shot consistent ignition.

[Ditchdigger]

Roudy the gun I'm shooting now,isn't a Hand but a CVA Optima Elite. Out of 60 rds. of Rem. brass I found 20 that weighed just right. My next trick is what Fred said about deburring of the primer holes.   Digger

[quickdtoo]

I use the Lyman primer pocket uniformer(comes in large or small) and flash hole uniformer. They can both be chucked in a drill to make quick work of the tasks, got mine at Midsouth.

Tim

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[AtlLaw]

Does anyone weigh their cases? if so:

I used to years ago but kinda got away from it.  For a long time I've just been sorting by headstamp since I found that, in the samples I've weighed anyway, there is a weight difference between them.  i.e.:  Winchester headstamp averages X gr. and  WW averages Y gr..  Someday I'll do my own little test and see at what point case weight difference has a noticeable effect on velocity (pressure).  I've got a new 30/06 that showed promise and got even better after I bedded it, plus I've got tons of '06 brass of various manufacture.

1.  What kind of tolerance do you use, +/_ .5 gr, +/_ 1.0 gr, ?

This is the exact question I want to answer.  But I probably wouldn't waste the time going under a gr, if that low.

2.  If one trims to the same length then weighs the cases is it still important to sort by brand?

I shouldn't think so.  The internal dimentions may vary, but I should think the volume would be the same under the circumstances you mention.

There is one important caviat here; Military brass.  It is significantly heavier then commercial brass which has a definate impact on case volume.  I cannot get within of 2 gr. of max published loads loading for my .308 (or .358 for that matter) using Lake City 7.62 brass.  In that case size, uh, I mean weight, does matter.